You know you're not at the average charity rock concert when you hear "This one's called Mauled ... to ... Fucking ... DEATH!" as a song introduction. And so it was at Boltfest, an event that death-metal veterans and John Peel favourites Bolt Thrower used not only to celebrate their 26th anniversary but also to raise money for Teenage Cancer Trust. However, in a move that would make your average charidee-pimping rock star blanche, they footed the entire bill for the event themselves. As they put it on the press release: "Well, you can't charge people to come to your birthday party." Thus all of the staggeringly cheap £5.99 entrance fee went to the trust, and Bolt Thrower's ambition of raising £10,000 was easily achieved.

With the doom supergroup Vallenfyre as unusually high-calibre festival openers, the Forum (who waived their usual booking charge) was bursting at the seams. Long-standing Brummie death-metallers Benediction didn't freeze in front of a such a large crowd, but unfortunately the same couldn't be said for Discharge. Blighted by technical problems and sounding distinctly under-rehearsed, the seminal hardcore punk act's legacy was poorly served by their performance. It was no coincidence that, during their set, the least busy area of this cavernous space was right in front of the stage.

Thankfully, US death metal pioneers Autopsy were less negligent with their own back catalogue, and a mix of pre- and post-reunion material brought the hirsute hordes back to the front of the hall. But it was left, appropriately, for the birthday boys (and girl) of Bolt Thrower to really raise the roof. "Are you ready for the big guns?" bellowed frontman Karl Willets before the chugging opening riff of World Eater was greeted with a massive roar of recognition. From there on in, the Coventry five-piece's bombast was relentless, and every monstrous battle hymn prompted a sea of banging heads. The charitable spirit has rarely rocked this hard.